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 A189244 The n-th derivative of e^((2-x-x^2)/(1-x-x^2)), evaluated at x=1. 1
 1, 3, -7, 9, 177, -3897, 65649, -1057851, 16606977, -238404789, 2305262889, 33442089057, -3560906733903, 182521828278351, -8055082800686367, 338022326927690397, -13915405899740874879, 566988435851123595411, -22784764731442383689127, 888283409438427072329529 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 COMMENTS The n-th derivative of exp((2-x-x^2)/(1-x-x^2) is A(n,x) = n!*sum(m=1..n, sum(k=m..n, binomial(k-1,m-1)*binomial(k,n-k)*(2*x+1)^(2*k-n) * (-x^2-x+1)^(-m-k))/m!). LINKS Alois P. Heinz, Table of n, a(n) for n = 0..388 Vladimir Kruchinin, Derivation of Bell Polynomials of the Second Kind, arXiv:1104.5065 [math.CO], 2011. FORMULA a(n) = n!*sum(m=1..n, sum(k=m..n, binomial(k-1,m-1) *binomial(k,n-k) * (-1)^(m+k)*3^(2*k-n))/m!), a(0)=1. E.g.f.: exp(x*(3+x)/(3*x+x^2+1)). - Alois P. Heinz, Sep 27 2016 MATHEMATICA f[x_] := E^((2 - x - x^2)/(1 - x - x^2)); a[n_] := Derivative[n][f][1]; Table[a[n], {n, 0, 20}] (* Jean-François Alcover, Jul 27 2018 *) PROG (Maxima) a(n):=n!*sum(sum(binomial(k-1, m-1)*binomial(k, n-k)*(-1)^(m+k) * 3^(2*k-n), k, m, n)/m!, m, 1, n) CROSSREFS Sequence in context: A087147 A152607 A118559 * A127789 A112105 A065501 Adjacent sequences:  A189241 A189242 A189243 * A189245 A189246 A189247 KEYWORD sign AUTHOR Vladimir Kruchinin, Apr 26 2011 STATUS approved

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Last modified June 20 05:01 EDT 2019. Contains 324229 sequences. (Running on oeis4.)